Gravel packing and fracturing equipment involves moving a slurry flow from an internal flow bore through an internal annulus in the tool and ultimately out an exterior wall to an outer annulus usually around screens. Typically the tool that is used is a crossover that can take various positions for delivery of fracturing fluid and at another time delivery of gravel slurry with other positions that allow removal of excess fluid through circulation or reverse circulation.
The gravel slurry is fairly abrasive and when combined with the flow rates that can occur in the crossover tool it often results in high wear of parts that receive an impact from the fluid stream as it changes direction within the tool. One effort to address the erosion issue within the tool is to provide a sleeve after the first turn from a central flow path to an internal annulus. In U.S. Pat. No. 7,096,946 such a sleeve 80 is rotatably mounted to turn on its longitudinal axis and the flowing slurry stream interacts with internal vanes 66. The objective here was to extend the wear of sleeve 80 by rotating it so that the slurry impinged on a full circumference on the inside wall of sleeve 80 rather than a fixed spot.
Other efforts to protect slurry outlet ports have focused on aperture liners that are slightly smaller than the aperture itself. These liners could be in the form of a sacrificial sleeve or inserts as for example illustrated in U.S. Pat. No. 5,636,691. Crossover tool assemblies in general are illustrated in U.S. Pat. No. 6,923,260. Vanes outside of sand screens assemblies for evenly distributing gravel after release from the crossover is shown in U.S. Pat. No. 4,995,456.
Spiral vanes have been used downhole in separator service such as illustrated in item 304 in U.S. Pat. No. 7,174,959 and item 20d in U.S. Pat. No. 4,273,509. Spiral vanes 112 in U.S. Pat. No. 4,132,075 are used to promote mixing to improve heat transfer in a geothermal application where turbulence is sought as an improvement to heat transfer rates. Spiral vanes can be combined with a centralizer to promote distribution of pumped cement for an annular space around a tubular as disclosed in U.S. Pat. No. 5,097,905.
To address an erosion problem with slurry outlet ports in downhole equipment and more particularly in crossover tool systems that deliver fracturing fluids and gravel slurries, the present invention proposes a technique to improve flow dispersion and reduce turbulence in the tool so as to decrease the exit velocity of slurry from ports to a lower rate and consequently reduce the erosion effect. The result is accomplished by inducing a swirl in at least a portion of the flowing stream with the beneficial result being that void spaces in an internal tool annulus are minimized which results in an effective increase in flow area which in turn leads to less turbulence, better filling of the annular volume with a resulting reduction in velocity and longer useful life for the ultimate exit ports into a surrounding annulus such as around gravel pack screens. These and other advantages of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and associated drawings while recognizing that it is the claims that determine the full scope of the invention.